Is it possible for an object moving with a constanilccof8.y d2/e9h97 r lwq u/ft speed to accelerate? Explainy 8 lec.i27dl oh9/9/rucw qff.

  Consider a particle moving w-rf rlir5z:dh c*ka86ith constant speed such that its acceleration of constant magnitude is always perp:fak cr8-r6z lr5i*dhendicular to its velocity.

  An object moves in a 895f xsr7ulq4x vajz- circular path at a constant speed. Compare the direction of the object's v9x5u4rqfs j8l- x7azv elocity and acceleration vectors.

  When an object experiences uniform circular motion, the direction m,i 9vqm - x ta6,/e2jsvn ez0fb/e9ukof the acceleratiom 9b aej6i ,ufst/ze0m 2q-kn vx,v9e/n is

  Consider a particle moving with constant speed s u;aqmf09)03bpsmi9vbzzlr, :fz :dsuch that its acceleration of constant magnitude is s9)p0mr:bm avsfiqfz zuzd ; ,9l:b3 0always perpendicular to its velocity.

  What type of acceleration does an object moving with consv8mx+ y19uch r z:goj*4*nt igtant speed in a circular path experienceing:r8 vg+uo49zmx**ct h1 y j?

  What force is needed to make an o qmp6p1vyu6aaa hx7/1 bject move in a circle?

  When an object experiences uniform circular motion, th 2oyic-z8 t;xhe direction of the net force isc2 tzo;h iy-x8

  A roller coaster car is on a track that forms a circula18ch ; vpvn yvr9ej5z/5sq-xdr loop in the vertical plane. If the car is to just maintain contact with trac-hvr;/5je zd8n 15q9vvsyc xp k at the top of the loop, what is the minimum value for its centripetal acceleration at this point?

  A roller coaster car (mass = M) is on a track that forms a cir w1sx+k28 ojx;3c2sn0r cdg nwcular loop (radius = r) in the vertical plane. If the car is to just maintain contact +n1;2x3sgw0nk d2 o xcw8rjscwith the track at the top of the loop, what is the minimum value for its speed at that point?

  A pilot executes a vertical dive then follows a semi-circular a .kpv 2jq +99uq 5i:xr)jvjqvwrc until it is going straight up. Just as the plane is at itq9 qj2+i.p)9j w x:v5kj qrvuvs lowest point, the force on him is

  A coin of mass $m$ rests on a turntable a distance $r$ from the axis of rotation. The turntable rotates with a frequency of $f$. What is the minimum coefficient of static friction between the turntable and the coin if the coin is not to slip?

  A car goes around a curve of radi,necxh-2 tk1d n3e h5zus $r$ at a constant speed $v$. What is the direction of the net force on the car?

  A car goes around a curve of radius r at a constant speed v. Then itpn 43),w +jwplqumm/,:ak jum goes around the same curve at half of the original speed. What is the centripetal force on then4 )wu ,jljmap+mw,m/q:3 puk car as it goes around the curve for the second time, compared to the first time?

  A car goes around a curve of radius r at a constant spii3 tg11is0ye(e qva.eed v. Then it goes around a curve of radius 2r at speed 2v. What is the cent11egyei ti i3.q0a(sv ripetal force on the car as it goes around the second curve, compared to the first?

  A car of mass m goes around a banked curve of radius r with spe9 3(o) / ockrxo(kbf6eu. byhked v. If the road is frictionless due to ice, the car can still negotiate the curve if the horizontal component of the normal force on the car from the road is equal in mb3fxh/9oyreku k6 () cob.k o(agnitude to

  Two horizontal curves on a bobsled run are banked at the same angle, but one hap m8h bqr8r,-krjo7l9p8uz,p s twice the r8jolpbmuprzr8q -7,9 8phk,r adius of the other. The safe speed (no friction needed to stay on the run) for the smaller radius curve is v. What is the safe speed on the larger radius curve?

  The banking angle in a turn on the Olympic bobsled track is not c e3 /xi gcexm ;lb 4e6+jpma,ca5tj6)jc( 7eueonstant, but increases upward from the horizontal. Coming around a tur4bgex ;)jeu3(txej, am7c+ p c6 e5/l ajemci6n, the bobsled team will intentionally "climb the wall," then go lower coming out of the turn. Why do they do this?

  Is it possible for an object moving around a circular path to haveg,e h/ x6i9lr+mc :xuu both centripetal and tangential acc:r x/eg+h96iu ,c ulmxeleration?

  The gravitational force between two objects is proportio)u/nygri: zgfqg (6vhf7l- l;nal to

  The gravitational force between two objects is inversely pb 9 , pdqkft(a qy3xlz4k4t/4vroportional to

  Two objects attract each other gravitationally. If the distance between theih n5o 2wpwdp 9j9cb728. avhmnr cp8 w7 jm95ndv2oha chp 92wbn.enters is cut in half, the gravitational force

  Two objects, with masses1n 0fuj o.mjvg7:j51pvs.vy f mv)pr: $m_{1}$ and $m_{2}$, are originally a distance r apart. The gravitational force between them has magnitude F. The second object has its mass changed to 2$m_{2}$, and the distance is changed to r/4. What is the magnitude of the new gravitational force?

  Two objects, with masses apd7 sn8 ,fb +xi,g*ky$m_{1}$ and $m_{2}$, are originally a distance r apart. The magnitude of the gravitational force between them is F. The masses are changed to 2$m_{1}$ and 2$m_{2}$, and the distance is changed to 4r. What is the magnitude of the new gravitational force?

State Newton's law of universalug k3f .;pg5cm gravitation.

  Compared to its mass on the Earth, the massfnt4 /x) w s oqu)e8,d*j1bliu of an object on the Moon is

  The acceleration of gravity on the Moon is one-sixth what it is on4xnjd ;/)9+rr6d :mepus)+c eignzi m Earth. An objectmirpg;dr9j+ s)cee +:/6x 4 nzm ud)in of mass
72 kg is taken to the Moon. What is its mass there?

  As a rocket moves away from thet)zk toxs0e)9/dtjzzp- e0w7 Earth's surface, the rocket's weight

  A spaceship is traveling to the Moon. At what point is it beyond + upyg8zrgtk+4jl3 .0 wz n5nx q7*rhzthe pull of Earth'sjhzzp*084 5uqgn 3+ tl.xr nkwz7gr+y gravity?

  Suppose a satellite were orbiting the Earth just above the qhhd9v6dy3 )jsurface. What is its centripetdhjq )dyv39 6hal acceleration?

  A hypothetical planet has a massjw;nqab*3i .ji( dh *d of half that of the Earth and a radius of twicedbqnj aii(*;hj* d 3w. that of the Earth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the Earth?

  The acceleration of gravity on the Moon is one-sixth what it i5.bk9 zx3qzvm)hcukd+2 k zx)s on Earth. The radius of the Moon is one-fourth that of the Earth. What is the Moz k)hudkb qzcz32k+mv9.xx)5 on's mass compared to the Earth's?

  Two planets have the same surface gravity, but z768isax 37bt knb* sbalqab8ku(e/8planet B has twice the radius of pla7sn*stakb bx/a3 b 8q88kzu76lb ai e(net A. If planet A has mass m, what is the mass of planet B?

  Two planets have the same surface gravity, but planet B has twim (:l9qx/h,kvr ch c(ice the mass of planet A. k (/,(mcqic:x9lv rhh If planet A has radius r, what is the radius of planet B?

  Consider a small satellite moving inyf v; hdk wtl0mk33 (ep7)qgt5 a circular orbit (radius r) about a spherical pt7 v3ml;fh t kkdgp03q)yw(e5lanet (mass M). Which expression gives this satellite's orbital velocity?

  Satellite A has twice the mass of satellite B, and rotates in the same orbit*6 x u8bliqduk76x+n l rv7wd1. C+*idl xrnul 1 67ubkq6w7xd 8vompare the two satellite's speeds.

  A person is standing on a scale in an elevator accelerating do,phd8yqcc; ns34+f h jwnward. Compare typ,sch dc j3n8q4+f;h he reading on the scale to the person's true weight.

  Who was the first person to realize that the planets move in elliptical paths l u)ma ap-by2o)pq29a ar) poaulm)b-aap2yq 29ound the Sun?

  The speed of Halley's Comet, while travel2 z e: dqaaomtv(107iling in its elliptical orbit around the Sun,27qdm 1z0vo a: at(lie

  Let the average orbital radius of a planet be R. Let th j;nv4e0nqca l7 .hhg,e orbital period be T. What e0;n gvn.4a7q,l jhc hquantity is constant for all planets orbiting the Sun?

  A planet is discovere w-w 3 w/5wm,bnbage;j*jnu w:d to orbit around a star in the galaxy Andromeda, with the same orbital diameter as the w;uawm /e ,*bjn:3-jw b5gwn wEarth around our Sun. If that star has 4 times the mass of our Sun, what will the period of revolution of that new planet be, compared to the Earth's orbital period?

  The average distancev ,sr+jz/k v.n from the Earth to the Sun is defined as one "astronomical unit" (AU). An asteroid orbits the Sun in one-third ,v jv/n r.+kszof a year. What is the asteroid's average distance from the Sun?

State Kepler's laws.sat6 p;7cet 5i

  List the four fundamental forces in nature.lsmc. 5b -h2xd9yvi 0uhzko2*

  An object moves with a constant spee5- g; r3lz. xbarw2g)n h(kkrhz1w:jqd of 30 m/s on a circular track of radius 150 m. What kkx w)wrhrhg(2zarn :1j3-. ;bg5qz lis the acceleration of the object?

  The maximum speed around a level curve is 30.0 km/h. What is thev :e8jwykw2cm /r o,w1 maximum speed around a curve with twice the rce8/ y,v w 1w2rjk:womadius? (Assume all other factors remain unchanged.)

  What is the centripetal acceleration of a point on the qu5wi c8gv ,t-perimeter of a bicycle whegutq5-v ci 8,wel of diameter 70 cm when the bike is moving 8.0 m/s?

  A point on a wheel rotating at 5.00 rev/s is located 0.200 m from the axis.umbk1 12*rzuoeof7 )p What is the centripetal accelerationu )o o711muz*rf2pbe k?

  How many revolutions per 7um/sw xzf.qb+l(b u,n/azi 2minute must a circular, rotating space station of radius 100/ibu2(/7 f zl.xbu zqw+, smna0 m rotate to produce an artificial gravity of $9.80 \; m/s^2$?

  A motorcycle has a mass of 250 kg. Itx .;1ov1s7 b5xvvvqy2 ohgf e6 goes around a 13.7 m radius turn at 96.5 km/h. What is the centripetal force on thyxvvf o725.1ghxo6 evvb1 ; qse motorcycle?

  A 0.50-kg mass is attached to the end of a 1.0-m1-d h*h xgk:x*t su*xs string. The system is whirled in a horizontal circular path. If the maximum tension thadu-*tx1hss**hxk g:x t the string can withstand is 350 N. What is the maximum speed of the mass if the string is not to break?

  A stone, of mass m, is attached to a strong string andz+azq9t*cdo 9 uiz6e8i 5i6xn whirled in a vertical circle of radius r. At the exad5ii6 xzc +9inzo*uz9t6a8 q ect top of the path the tension in the string is 3 times the stone's weight. The stone's speed at this point is given by

  A stone, of mass m, is attached to a stron8 r5r4iyff s)4nzxj ;n 7fty6zg string and whirled in a vertical circle of radiusnyr zz)t6 njf45 7yfrs;4fx8 i r. At the exact bottom of the path the tension in the string is 3 times the stone's weight. The stone's speed at this point is given by

  A jet plane flying 600 m/s /tw7wo8 egct*m*)m xewzu+ + aexperiences an acceleration of 4g when pulling out of the dive. What is the radius of curvatur+ma+wm gc7tx* e wz*ew)o8u/te of the loop in which the plane is flying?

  A pilot makes an outside vertical loopw;p ;ut47 .qq*nrtczv (in which the center of the loop is beneath him) of radius 3200 m. At the top of his loop he is pushing down on his seat with only one-half of his normal weight. How fast is he gonrtp 4t uq7wcqvz*; .;ing?

  The maximum force a pilot can stand is about t5-pte899bl0auxbk g seven times his weight. What is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tol9-t0ag9l 8b pt5 kuebxerate at a speed of 250 m/s?

  A car traveling 20 m/s rounds an 80-m radius horizontal curve with the p+3 87doh8.avyfzcz0w foaq92 t kw2otires on the verge of slippingwp 7czoav 2af2q38 hf9wkoz.0yo+d 8t. How fast can this car round a second curve of radius 320 m? (Assume the same coefficient of friction between the car's tires and each road surface.)

  A car is negotiating a flat curve of radius 50 m with a speed of 20 ju* nr/5l-bchm/s. The centripetal forcrblj nhu/- *5ce provided by friction is $1.2 \times 10^{4} \; N$. What is the mass of the car?

  A car goes around a npod+i 8tkn0.flat curve of radius 50 m at a speed of 14 m/s. What must be the minimum coefficient of friction between the tires an0p8dni k+.no td the road for the car to make the turn?

  A car is moving with a constan(u7p:(lur h ;rvmr te.t speed v around a level curve. The coefficient of friction between the tires and the road is 0.40. What is the minimum radius o(v7 r pte.uur;r m:lh(f the curve if the car is to stay on the road?

  What minimum banking angle is required for an Olympic bobsled to qqb o;:dz,jw1sb e t6)-bayp3 negotiate a 100-m radius turn at 35 m/s without skiddiytb)jp1:-s d,6eoz3; wbqb aq ng? (Ignore friction.)

  A horizontal curve on a bobsled runt ;p5k8k(tb2 wpzs 7xh is banked at a $45^{\circ}$ angle. When a bobsled rounds this curve at the curve's safe speed (no friction needed to stay on the run), what is its centripetal acceleration?

  A frictionless curve of radius*dylf:cqkybo;j bgh 2 c-8/:m 100 m, banked at an angle of $45^{\circ}$, may be safely negotiated at a speed of

  A curve of radius 80 m is bankeuzxv a1/o, qs5- z5 a5ekqp0dud at $45^{\circ}$. Suppose that an ice storm hits, and the curve is effectively frictionless. What is the safe speed with which to take the curve without either sliding up or down?

  A 175-kg ball on the end of a string is revolving uniformly in a horizo ;dpa4 r;8nhoncyh6o;tqc: 4s3aoz ;wntal circle of radius 0.50;; whzy;n3coorc 6n4oapqad 4 ;8th:s0
m. The ball makes 2.00 revolutions in a second. (only fill in numerial value in the blanks)
(a) Determine the speed of the ball.    $m/s$
(b) Determine the ball's centripetal acceleration.    $m/s^2$
(c) Determine the force a person must exert on opposite end of the string.    $N$

  Starting from rest in the pit area, a race car accelerates at a uni2 kzfi.*o wllr nd+2z1e-jm-un +ov5rform rate to a speed of 45 m/sn o.*vfo5kmrzild +2-uz ne2wrl j+ -1 in 15 s, moving on a circular track of radius 500 m. (only fill in numerical value in the blanks)
(a) Calculate the tangential acceleration.    $m/s^2$
(b) Calculate the radial acceleration when the instantaneous speed is equal to 30 m/s.    $m/s^2$

  The hydrogen atom consists of a proton of mas9q couds r*y48 ;yehbgj u;qa;l3k q6*t 4akk0s $1.67 \times 10^{-27} \; kg$ and an orbiting electron of mass $9.11 \times 10^{-31} \; kg$. In one of its orbits, the electron is $5.3 \times 10^{-11} \; m$ from the proton. What is the mutual attractive force between the electron and proton?

  What is the gravitational force on a 70-kg person standinvb io/ g hu+c; a6xh/0+j1gilmg on the Earth, due to the Moon? The mass of the Moong h6iij+/ ovb1hgclau 0x;/ m+ is $7.36 \times 10^{22} \; kg$ and the distance to the Moon is $3.82 \times 10^{8} \; m$.

  The gravitational attractive force between two masses is F. If;go ln(ph hio5s)z8x / the masses are moved to half of their initial distance, what is the gravitation;zp)h5oin (8 og hl/xsal attractive force?

  For a spacecraft going from the Earth toward the Sun, at what distanl04rn6 eu; 4 rjphq0z l4yz3m7 ryoyw9ce from the Earth will the gravitatih;7p 4 4j mryru0 z3y9owzy 4llq0nre6onal forces due to the Sun and the Earth cancel?
Earth's mass: Me = $5.98 \times 10^{24} \; kg$ the Sun's mass: Ms = $1.99 \times 10^{30} \; kg$
Earth-Sun distance: r = $1.50 \times 10^{11} \; m$

  The mass of the Moon i nn p*p3wyb/m-s $7.4 \times 10^{22} \; kg$ and its mean radius is $1.75 \times 10^{3} \; km$. What is the acceleration due to gravity at the surface of the Moon?

  An astronaut goes out for a "space-walk" at a distance above the Earth e)eot/l/ czrtq-s8ly6cr;d i4qual to the radius of the Earth. What is her acce y)4r6d /erz to8ctlsqlci/;-leration due to gravity?

  The radius of the Earth is Rbv1a7b*z8 zq5rx u( a0 7qvjea. At what distance above the Earth's surface will the accelerationbaarv0z*7z v(axq qb 8 75eu1j of gravity be $4.9 \; m/s^2$?

  A satellite encircles Mars at a distance above its surface equalqb+z4c*s/ d( 1beutmae6k.v k: +hgea to 3 times the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleratioad1eus6e b zqvkcb+/m4 +.g (h*a:kte n of gravity on the surface of Mars, is

  At a distance of 14000 km frsmo2/da o o5 -n3if,r ljwqfw.q.+g 3xom some planet's center, the acceleration of gravitywaj +lw3q2m,. -dors/q f gni5. oo3fx is $32 \; m/s^2$. What is the acceleration of gravity at a point 28000 km from the planet's center?

  An object weighs 432 N on the surf6zr rbb h)he5;ace of the Earth. The Earth has radius r. If the object is raised to a height of 3r above the Earth's surface, what is its w5h;rb ezhb)r6 eight?

  By how many newtons does the weight of a 100-kg peqidref7 .l8+z5+s mz trson change when he goes from sea level to an altitude of 5000 m? (The meaqi ler+.tmz87z +d5s fn radius of the Earth is $6.38 \times 10^{6} \; m$.)

  The Earth has radius r. A satellite of mass 100 kg is at a wrxld;f 8s),z point 3r above the Earth's surface. What is the satellite's wlf8xsr;d )z w,eight?

  A spherically symmetric planet has four x6: pzuwcyy + x7azf6v tai4+/times the Earth's mass and twice its radius. If a jar of peanut butter weighs 12 N on the surface of the Earth, how much would it weigh on thepyf: +a+/y64vzut 7a ixc6zxw surface of this planet?

  During a lunar eclipse, the Moon, Earth, and Sun all lie on the 9w*w, 8bhuc kqsame line, with the Earth between the Moon h,ku bqc9w8w*and the Sun. The Moon has a mass of $7.36 \times 10^{22} \; kg$; the Earth has a mass of $5.98 \times 10^{24} \; kg$; and the Sun has a mass of $1.99 \times 10^{30} \; kg$. The separation between the Moon and the Earth is given by $3.84 \times 10^{8} \; m$; the separation between the Earth and the Sun is given by $1.496 \times 10^{11} \; m$.
(a) Calculate the force exerted on the Earth by the Moon, its magnitude is    $\times 10^{20} \; N$, its direction is  ----待选择----towardsaway from  the moon.
(b) Calculate the force exerted on the Earth by the Sun, its magnitude is    $\times 10^{22} \; N$, its direction is  ----待选择----towardsaway from  the Sun.
(c) Calculate the net force exerted on the Earth by the Moon and the Sun, its magnitude is    $\times 10^{22} \; N$, its direction is  ----待选择----towardsaway from  the Sun.

  A 2.10-kg brass ball is transported to the Moon.i/jbfl r4i p3*
(a) Calculate the acceleration due to gravity on the Moon.    $m/s^2$ (The radius of the Moon is $1.74 \times 10^{6} \; m$ and the mass of the Moon is $7.35 \times 10^{22} \; kg$)
(b) Determine the mass of the brass ball on the Earth    $kg$ and on the Moon    $kg$
(c) Determine the weight of the brass ball on the Earth    $N$
(d) Determine the weight of the brass ball on the Moon    $N$

  A satellite is in a low circular orbit about the E6./ yccch mgg)arth (i.e., it just skims the surface of the Earth). What is the speed of the satellite? (The mean radius ofmhcyg.g6 )c/c the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in a low circular orbit about the Earth (i.e., it just skims the x *eh3jj qgfo;arf6(bos; k19surface of the Earth). obj rff;1k; js3 9aqego6*hx( How long does it take to make one revolution around the Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  A satellite is in circular orbit 230 km a(e ur yoxid;b+o9 lodd-u6(v,bove the surface of the Earth. It is observed to((ve;ybdduodrx9i +,l u-6 o o have a period of 89 min. What is the mass of the Earth? (The mean radius of the Earth is $6.38 \times 10^{6} \; m$.)

  Europa, a moon of Jupiter, has an orbi9ho5)t:ci hb4efd m.mtal diameter of $1.34 \times 10^{9} \; m$, and a period of 3.55 days. What is the mass of Jupiter?

  The innermost moon of Jupu1:n6e ct v:yziter orbits the planet with a radius of $422 \times 10^{3} \; km$ and a period of
1.77 days. What is the mass of Jupiter?

  Two moons orbit a planet in nearly circular orbits. Moon A has onut,tbko v4 q,zp.9ylo3j.e6 v,rp8vrbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete one orbit. How long does it take m9,vne3ry.,4vb8k tqtpjlpzu ,o6. o voon B to complete an orbit?

  The planet Jupiter irdxfzo7vhlg3 s 4d-z je /(7o:s $7.78 \times 10^{11} \; m$ from the Sun. How long does it take for Jupiter to orbit once about the Sun? (The distance from the Earth to the Sun is $1.50 \times 10^{11} \; m$.)

  It takes the planet Jupiter jtv7b* ji .dytp9fq 3a4gth0xr92)hc 12 years to orbit the Sun once. What is the average distance from Jupiter to the Sun? (The dis)cdj f4p .g9*at b hv73tit90 2hyqjrxtance from the Earth to the Sun is $1.5 \times 10^{11} \; m$.)